We have developed the Halpin system to implement our multimodal conversational model for information retrieval. This dialogue-oriented interface allows the access to a digital library database, on the internet, in a natural language way, and gives its oral responses via usual browsers. The results of the first experiments show that the Halpin system provides some interesting dialogues (in particular with the beginners), according to the users goals and skills, that leads to information retrieval success, while searches with the original user interface (traditional web form) failed.